Bertie was the first to try and take over a crystal point in Tokyo, and also the first to send one of the Negamoon's droids. Eventually she played chess against Amy (Sailor Mercury) in a tournament and lost, so she did a "freeze play" chess with her that whenever she lost a piece, she would be frozen. Tuxedo Mask broke the spell, however, and Prizma and Avery told her that Rubeus was going to kick her out, so she attempted to freeze herself to death, but Catzi stopped her and convinced her to turn good, where she was healed by Sailor Moon using Moon Crystal Healing Activation. From here, she worked with Catzi at the cosmetic shop.
Bertie attacks with dark water.
In the Japanese version, she is the second youngest (as Catzi is portrayed as the youngest), and her name is Berthier.